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The basic facility of the Factory of Superheavy Elements (SHE), the DC-280 cyclotron, in the Flerov Laboratory of Nuclear Reactions at the Joint Institute for Nuclear Research has been completed. Both new and experimentally tested engineering solutions of the laboratory underlie the project. Planned beam intensities of up to 10 pμA of ions with average masses (A ~ 50) are one order of magnitude higher than those produced at the U-400 cyclotron up to now. From 2016 to 2018, the DC-280 cyclotron equipment was installation and set up. The first 84Kr14+ ion beam was accelerated in the DC-280 on December 26, 2018, and extracted to the accelerated ion transportation channel on January 17, 2019. In March 2019, beams of accelerated 84Kr+14 ions with an intensity of 1.36 pμA and 12С+2 ions with an intensity of 10 pμA were extracted from the DC-280 to the beam transportation channel with an energy of about 5.8 MeV/nucleon. The main task of the new accelerator is to implement a long-term research program at the SHE Factory aimed at the synthesis of new elements (Z ≥ 119) and a detailed study of nuclear–physical and chemical properties of previously discovered elements nos. 112–118.

The status of the project of the DC-280 cyclotron is presented. The DC-280 will be the basic facility of the Super Heavy Element Factory which is being created at the FLNR JINR. The energy of the ions extracted from the cyclotron will be vary from 4 up to 8 MeV/amu. The expected ion beam intensity at DC-280 extraction is 10 pμA for ions with masses of 50–60. The main parts of the DC-280 are already made and are being assembled. In according to FLNR plans the cyclotron has to be assembled in the period from 2016 to 2017. The cyclotron commissioning will be in 2018.

A high intensity ion beam of 50Ti ions was obtained using the ECR ion source on the U400 cyclotron. The experimental tests using accelerated 50Ti ions were performed with a modernized VASSILISSA separator (SHELS). Data has been obtained on the transmission coefficients of recoil nuclei synthesized in complete fusion reactions. Estimates from ion optical calculations performed in the design phase of the project of modernizing the separator are completely confirmed.

The design of the high-voltage axial injection system for the DC-280 cyclotron that is being constructed at the Flerov Laboratory of Nuclear Reactions (FLNR) at the Joint Institute for Nuclear Research (JINR) is presented. The injection system will make it possible to efficiently inject ions of elements ranging from helium to uranium with the ratios of their atomic mass to the charge varying from 4 to 7.5.

Neutron emission was observed experimentally at the DC-60 cyclotron at the Institute of Nuclear Physics (Astana, Kazakhstan). The neutron yields were measured in the bombardment of light-element (Be, C, Al, Al2O3, and LiF) targets with heavy ions (Ar, Kr, and Xe) with energies below the Coulomb barrier. The angular distributions of neutrons from the targets were also measured. It was found that the observed neutrons were produced in secondary nuclear reactions between the resting target nuclei and recoil nuclei that acquire energy in the process of elastic scattering. The experimental results were compared with calculations based on the abovementioned secondary-reaction mechanism. The calculations allow one to estimate the yields of secondary reactions to within a coefficient of 2.

Neutron yields during irradiation of structural metals and polymer film by argon, krypton, and xenon ions with 2.4 and 2.5 MeV/nucleon energies are measured on the CYTRACK and DC-110 cyclotrons. The angular distributions of neutrons from the target are measured. The LISE++ is used for extrapolating the data obtained to other ions, their energy, and to other targets. The program was tested on experimental data found in the literature. As a result of comparison, it is established that the calculation results coincide with the experimental data within a coefficient of two.

In Flerov’s Laboratory of Nuclear Reactions of JINR in the framework of project “Beta” a cyclotron complex for a wide range of applied research in nanotechnology (track membranes, surface modification, etc.) is created. The complex includes a dedicated heavy-ion cyclotron DC-110, which yields intense beams of accelerated ions Ar, Kr and Xe with a fixed energy of 2.5 MeV/A. The cyclotron is equipped with external injection on the base of ECR ion source, a spiral inflector and the system of ions extraction consisting of an electrostatic deflector and a passive magnetic channel. The results of calculations of the beam dynamics in measured magnetic field from the exit of spiral inflector to correcting magnet located outside the accelerator vacuum chamber are presented. It is shown that the design parameters of ion beams at the entrance of correcting magnet will be obtained using false channel, which is a copy of the passive channel, located on the opposite side of the magnetic system. Extraction efficiency of ions will reach 75%.

The DC-110 heavy ion cyclotron for industrial production of track membranes has been developed and created at the Laboratory of Nuclear Reactions of the Joint Institute for Nuclear Research. The cyclotron is equipped with an electron cyclotron resonance ion source operating at a frequency of 18 GHz. The accelerator complex was put into operation in 2012 and 40Ar6+, 86Kr13+, and 132Xe20+ ion beams with a energy of 2.5 MeV/nucleon and intensity of 13, 14.5, and 10.5 μA, respectively, were produced. Irradiation of a polymer film was carried out on a specialized channel and track membranes with a high uniformity of pores were obtained. The DC-110 accelerator complex can produce up to 2 million square meters of track membranes per year.

A heavy ion acceleration complex for industrial applications based on the DC-110 cyclotron has been developed at the Laboratory of Nuclear Reactions, Joint Institute for Nuclear Research. It is planned to irradiate polymer films with a width of up to 600 mm at this complex. This paper presents a design of a system for scanning heavy ion beam which offers uniform film irradiation at a beam energy of up to 2.5 MeV/nucleon. The general concept of the two-channel scanning system and the design of the main deflecting magnets are described.

The DC-350 accelerator complex is described and its technical characteristics are presented.

An monitor for control of accelerated particle flux density used in irradiation of polymer films with heavy ions with a low track density (103−5 × 107 cm−2) is based on detection of recoil protons. It has been designed to control irradiation of a film with a width of up to 650 mm and is composed of five PIN diodes with a hydrogenous target placed in front of each diode. The sensitivity of the monitor with a polyethylene target to the density of a xenon ion beam is described by a linear function; its value is (4.0±0.5) × 10−3 pulses/(ion/cm2). The instrument is capable of monitoring ion flux densities of

The cyclotron IC-100 station, based on the Laboratory of Nuclear Reactions (JINR, Dubna, Russia), provides the industrial construction of nuclear filters. During modernization, the cyclotron was equipped with a superconducting ECR-ion source and an axial injection system. The specialized beam channel with a two coordinate scanning system and equipment for irradiating polymer films was installed in the implantation part of the station. High intensity heavy ion beams of Ne, Ar, Fe, Kr, Xe, I, and W have been accelerated to 1 MeV/nucleon energy. The investigation into irradiated crystals features and irradiation of different polymer films is provided. Also, a few thousands square meters of track films with holes in the wide range of densities were produced. The cyclotron-based station is capable of solving different kinds of scientific and applied problems as well.

The vacuum system of the heavy ion cyclotron complex DC-60 created at the Flerov Laboratory of Nuclear Reactions of the Joint Institute for Nuclear Research for the interdisciplinary research complex (Astana, Kazakhstan) is described. The results of numerical simulation of transmission efficiency of accelerated ions in the course of recharging on residual gas, which determines the basic parameters of the designed vacuum system, are presented. As a result of successful implementation of the cyclotron complex DC-60 project, heavy ion beams were accelerated. The obtained parameters of the vacuum system agree completely with calculations, which were the basis of the project.

Industrial production of nuclear filters has been implemented at the IC-100 cyclotron complex of the Laboratory of Nuclear Reactions at the Joint Institute for Nuclear Research. After the complete upgrade, the cyclotron was equipped with the superconducting ECR ion source and the system of external axial beam injection. The implantation complex was equipped with the special transportation channel with the beam scanning system and the setup for irradiation of polymer films. Intense beams of heavy ions Ne, Ar, Fe, Kr, Xe, I, and W with an energy of ∼1 MeV/nucleon were obtained. the properties of irradiated crystals were studied, different polymer films were irradiated, and several thousands of square meters of track membranes with pore densities varying in a wide range were produced. Other scientific and applied problems can be solved at the cyclotron complex.

An accelerator complex has been developed on the basis of the DTs-60 cyclotron for performing scientific and applied research and for commercial application in nanotechnology. The complex was designed and constructed at the Laboratory of Nuclear Reactions of the Joint Institute for Nuclear Research for the Interdisciplinary Scientific and Research Center at the L. N. Gumelev Eurasian National University (Kazakhstan). Intense beams of heavy ions of Ne, Ar, Kr, and other elements have been obtained and accelerated in the cyclotron. Various polymer films have been irradiated and several control batches of track membranes have been prepared in a wide range of densities of the openings. The complex is a unifying factor in the development of technologies, science, and science-intensive business and is intended for producing track filters, developing commercial technologies using nano-and microstructures based on nuclear membranes and for creating a scientific environment in Kazakhstan.

Since 2010 the Russian Federal Space Agency (Roscosmos) has been utilizing SEE testing facilities at the Flerov Laboratory of Nuclear Reactions (FLNR) of the Joint Institute for Nuclear Research (JINR) in Dubna. The FLNR has abundant experience in development, creation and using heavy ion cyclotrons, ECR ion sources and auxiliary systems. The FLNR Accelerating Complex consists of four isochronous cyclotrons, two of them: U400 and U400M are used in programs of SEE testing with heavy ions. At present time, the accelerators equipped by four specialized beam lines for SEE testing. Beams of elements from Li to Bi in two energy ranges: 3 ÷6 MeV/nucleon (lower range) and 20 ÷50 MeV/nucleon (upper range) are available to users. Specialized beam lines provide irradiating areas up to 300 cm2 for the lower range and up to 28 cm2 for the upper one. Beam inhomogeneity over the irradiating area is not worse than 20%. On-line and ex situ diagnostics of the main experimental parameters have been provided. Annual operation of U-400 and U-400M is about 6000 hours each. Annual operation of SEE testing facilities at FLNR is about 2000 hours. The future FLNR plans of SEE testing development are presented.

A cyclotron complex has been developed at the Laboratory of Nuclear Reactions, Joint Institute for Nuclear Research, for a wide spectrum of applied studies in the field of nanotechnologies (template technologies, track membranes, surface modification, etc.). This complex includes a specialized DC-110 cyclotron, which gives high intensity beams of accelerated Ar, Kr, and Xe ions with a fixed energy of 2.5 MeV/nucleon. This cyclotron is equipped by an external injection system with an ECR ion source operating at a frequency of 18 GHz. The cyclotron electromagnet with a pole diameter of 2 m offers a working magnetic field on a level of 1.67 T. The fixed RF frequency is 15.5 MHz. The beam is extracted from the cyclotron by the electrostatic deflector. The main parameters of DC-110 cyclotron are presented in this paper.

The stability of heavy nuclides, which tend to decay by α-emission and spontaneous fission, is determined by the structural properties of nuclear matter. Nuclear binding energies and lifetimes increase markedly in the vicinity of closed shells of neutrons or protons (nucleons), corresponding to ‘magic’ numbers of nucleons; these give rise to the most stable (spherical) nuclear shapes in the ground state. For example, with a proton number of Z = 82 and a neutron number of N = 126, the nucleus 208Pb is ‘doubly-magic’ and also exceptionally stable. The next closed neutron shell is expected at N = 184, leading to the prediction of an ‘island of stability’ of superheavy nuclei, for a broad range of isotopes with Z = 104 to 120 (refs 1, 2). The heaviest known nuclei have lifetimes of less than a millisecond, but nuclei near the top of the island of stability are predicted to exist for many years. (In contrast, nuclear matter consisting of about 300 nucleons with no shell structure would undergo fission within about 10−20 seconds.) Calculations3,4,5 indicate that nuclei with N > 168 should already benefit from the stabilizing influence of the closed shell at N = 184. Here we report the synthesis of an isotope containing 114 protons and 173 neutrons, through fusion of intense beams of 48Ca ions with 242Pu targets. The isotope decays by α-emission with a half-life of about five seconds, providing experimental confirmation of the island of stability.

The reaction 48Ca+238U was investigated at the recoil separator VASSILISSA at the Flerov Laboratory of Nuclear Reactions, JINR Dubna, in attempts to synthesize new isotopes of element 112. The experiments were performed at two beam energies resulting in excitation energies of the compound nucleus of 33 and 39 MeV. The collected beam dose was 3.5 × 1018 and 2.2 × 1018, respectively. Two spontaneous fission events were observed at the lower beam energy, which tentatively were assigned to the new neutron rich isotope 283112 produced in the reaction 238U(48Ca,3n)283112. The measured cross-section is (5.0+6.3−3.2) pb and the half–life is (81+147−32) s. No event was observed at the higher beam energy resulting in the upper cross–section limit of 7.3 pb.

The construction of the DC-60 Heavy Ion Cyclotron for the Interdisciplinary Scientific Research Complex (ISRC) in Astana started in early 2004. The cyclotron was manufactured and tested at the Flerov Laboratory of Nuclear Reactions (FLNR) in Dubna. The main units were delivered to Astana and assembled in the ISRC building in the summer of 2006. The cyclotron was turned on in September, 2006. The first heavy ion beams in the whole A/Z and energy ranges were accelerated and extracted in December, 2006.

It is shown that using a wide aperture magnetic lens without poles provides additional possibilities for improving the efficiency of scanning the systems of cyclotron beams for the following reasons: (1) The increase in the angle of deflection and, therefore, the length of the channel is reduced. (2) There is the possibility of improving the homogeneity of irradiation due to profiling magnetic conductors. (3) It is possible to align the fall angles of ions at edges of a target.

Aim of this report is to describe the main features of the Russian Federal Space Agency (Roscosmos) facilities which has been developed recently and will develop next year for SEE testing of the electronic devices at U400M cyclotron in Flerov Laboratory of Nuclear Reactions, Joint Institute for Nuclear Research, Dubna. At present specialized ion beam line with energy of 3÷6 MeV/nucleon O, Ne, Ar, Fe, Kr, Xe, Bi ions covering the LET range 4.5–100 MeV/(mg/cm2) is available to users. The project of ion beam line with ion energy up to 40 MeV/nucleon is presented too.

The decay properties of the new isotope ${}^{282}113$ and its daughter nuclei have been measured in the $^{237}\mathrm{Np}$($^{48}\mathrm{Ca}$, $3n$)${}^{282}113$ reaction. During an irradiation with a beam dose of $1.1\ifmmode\times\else\texttimes\fi{}{10}^{19}244$-MeV $^{48}\mathrm{Ca}$ projectiles, two decay chains originating from the odd-odd isotope ${}^{282}113$ $({E}_{\ensuremath{\alpha}}=10.63\ifmmode\pm\else\textpm\fi{}0.08\phantom{\rule{0.3em}{0ex}}\mathrm{MeV},{T}_{\ensuremath{\alpha}}={73}_{\ensuremath{-}29}^{+134}\phantom{\rule{0.3em}{0ex}}\mathrm{ms})$ were produced in the complete fusion reaction with a cross section of $0.{9}_{\ensuremath{-}0.6}^{+1.6}$ pb; these properties are all in agreement with expectations based on the results of previous experiments.

The decay properties of {sup 290}116 and {sup 291}116, and the dependence of their production cross sections on the excitation energies of the compound nucleus, {sup 293}116, have been measured in the {sup 245}Cm({sup 48}Ca,xn){sup 293-x}116 reaction. These isotopes of element 116 are the decay daughters of element 118 isotopes, which are produced via the {sup 249}Cf+{sup 48}Ca reaction. They performed the element 118 experiment at two projectile energies, corresponding to {sup 297}118 compound nucleus excitation energies of E* = 29.2 {+-} 2.5 and 34.4 {+-} 2.3 MeV. During an irradiation with a total beam dose of 4.1 x 10{sup 19} {sup 48}Ca projectiles, three similar decay chains consisting of two or three consecutive {alpha} decays and terminated by a spontaneous fission (SF) with high total kinetic energy of about 230 MeV were observed. The three decay chains originated from the even-even isotope {sup 294}118 (E{sub {alpha}} = 11.65 {+-} 0.06 MeV, T{sub {alpha}} = 0.89{sub -0.31}{sup +1.07} ms) produced in the 3n-evaporation channel of the {sup 249}Cf+{sup 48}Ca reaction with a maximum cross section of 0.5{sub -0.3}{sup +1.6} pb.

In Laboratory of nuclear reactions there are 4 accelerators of heavy ions. Cyclotrons U 400, U 400M, U 200 and DC-40 accelerate ions from Р up to Bi with energy from 3 up to 100 MeV/nucleon with high intensity. The large program of scientific and applied researches is carried out on the beams of heavy ions. In Laboratory the project DRIBs allowing obtaining beams of the accelerated radioactive ions is being realized. The first experiments on 6 He and 8 He beams are carried out.

We have studied the dependence of the production cross sections of the isotopes {sup 282,283}112 and {sup 286,287}114 on the excitation energy of the compound nuclei {sup 286}112 and {sup 290}114. The maximum cross section values of the xn-evaporation channels for the reaction {sup 238}U({sup 48}Ca,xn){sup 286-x}112 were measured to be {sigma}{sub 3n}=2.5{sub -1.1}{sup +1.8} pb and {sigma}{sub 4n}=0.6{sub -0.5}{sup +1.6} pb; for the reaction {sup 242}Pu({sup 48}Ca,xn){sup 290-x}114: {sigma}{sub 2n}{approx}0.5 pb, {sigma}{sub 3n}=3.6{sub -1.7}{sup +3.4} pb, and {sigma}{sub 4n}=4.5{sub -1.9}{sup +3.6} pb. In the reaction {sup 233}U({sup 48}Ca,2-4n){sup 277-279}112 at E*=34.9=2.2 MeV we measured an upper cross section limit of {sigma}{sub xn}{

We have studied the excitation functions of the reactions $^{244}\mathrm{Pu}$($^{48}\mathrm{Ca}$,$xn$). Maximum cross sections for the evaporation of 3--5 neutrons in the complete-fusion reaction $^{244}\mathrm{Pu+}^{48}\mathrm{Ca}$ were measured to be ${\ensuremath{\sigma}}_{3n}=2\phantom{\rule{0.3em}{0ex}}\text{pb}$, ${\ensuremath{\sigma}}_{4n}=5\phantom{\rule{0.3em}{0ex}}\text{pb}$, and ${\ensuremath{\sigma}}_{5n}=1\phantom{\rule{0.3em}{0ex}}\text{pb}$. The decay properties of $3n$-evaporation product $^{289}114$, in the decay chains observed at low $^{48}\mathrm{Ca}$ energy coincide well with those previously observed in the $^{244}\mathrm{Pu+}^{48}\mathrm{Ca}$ and $^{248}\mathrm{Cm+}^{48}\mathrm{Ca}$ reactions and assigned to $^{288}114$. Two isotopes of element 114 and their descendant nuclei were identified for the first time at higher bombarding energies: $^{288}114$ (${E}_{\ensuremath{\alpha}}=9.95\phantom{\rule{0.3em}{0ex}}\text{MeV}$, ${T}_{1∕2}=0.6\phantom{\rule{0.3em}{0ex}}\mathrm{s}$) and $^{287}114$ (${E}_{\ensuremath{\alpha}}=10.04\phantom{\rule{0.3em}{0ex}}\text{MeV}$, ${T}_{1∕2}=1\phantom{\rule{0.3em}{0ex}}\mathrm{s}$). We also report on the observation of new isotopes of element 116, $^{290,291}116$, produced in the $^{245}\mathrm{Cm}+^{48}\mathrm{Ca}$ reaction with cross sections of about $1\phantom{\rule{0.3em}{0ex}}\text{pb}$. A discussion of self-consistent interpretations of all observed decay chains originating at $Z=118$, 116, and 114 is presented.

This paper presents results of experiments aimed at producing long-lived superheavy elements located near the spherical shell closures with Z ≥114 and N ≥172 in the reactions of neutron-rich isotopes 244Pu, 245,248Cm and 249Cf with 48Ca projectiles. The decay properties of the synthesized nuclei are consistent with the consecutive α-decays originating in the decays of parent nuclides 289114, 290,291,293116 and 294118 produced in the 2n and 3n-evaporation channels. The present observations can be considered to be experimental evidence of the existence of the “island of stability” of superheavy elements.

We present the observation of the first decay event of the new nuclide {sup 292}116 in the running experiment on the synthesis of Z=116 nuclei in the reaction {sup 248}Cm+{sup 48}Ca. The experiment is in progress at FLNR, JINR, Dubna.